(1) Field of the Invention
This invention relates to a composition comprising a cyclopentanone or cyclopentanol compound having cyclopentylidene and/or cyclopentyl substituents at a high concentration, a process for preparing the same, and a perfume composition comprising the same as a fragrant odor-emitting ingredient.
The perfume composition is used, for example, for a perfume, a soap, a shampoo, a hair-treatment, a body shampoo, a detergent, a cosmetic, a hair-spray and an aromatic.
(2) Description of the Related Art
It is known that cyclopentanone derivatives include those which are useful as a perfume. As specific examples of the cyclopentanone derivatives used as a perfume, there can be mentioned methyl 3-oxo-2-(cis-2-pentenyl)-cyclopentaneacetate (trivial name: methyl jasmonate) and methyl 2-pentyl-3-oxocyclopent-1-yl-acetate (trivial name: methyl dihydrojasmonate), which are known as a perfume emitting a jasmine-like floral scent or odor; and 2-cyclopentyl cyclopentylcrotonate which is known as a perfume emitting a fruity and juicy scent or odor. That is, cyclopentanone derivatives having various substituents or functional groups are known as a perfume emitting a fragrant scent or odor.
As a perfume having a cyclopentanone structure with a cyclopentyl derivative substituent, only a few perfumes are knwon which include 2-cyclopentyl cyclopentylcrotonate, mentioned above, and 2-cyclopentylcyclopentanone.
As for a cyclopentanone compound having two cyclopentyl derivative substituents, it is taught in Bull. Soc. Chim. Fr., (1973) 4(2), 1509 that, when cyclopentanone is treated with metallic sodium, 2-cyclopentylidenecyclopentanone and 2,5-dicyclopentylidenecyclopentanone are produced. But, this literature is silent on yield of the dipentylidene compound. Further it is taught in J. Am. Chem. Soc., (1974), 116, 1962 that, when cyclopentanone is heated in the presence of a zeolite in a toluene medium, 2-cyclopentylidenecyclopentanone and 2,5-dicyclopentylidenecyclopentanone are produced. The yield of 2,5-dicyclopentylidenecyclopentanone is only 8%. The two literatures are silent on the use of 2,5-dicyclopentylidenecyclopentanone as a perfume.
Further, it is described in Shin Jikken Kagaku Kouza, vol. 14 (II), p852 (published by Maruzen, Japan) that, when cyclopentanone is allowed to react with potassium hydroxide in an ethanol medium, 2,5-dicyclopentylidenecyclopentanone is produced in a yield of 12-51%. However, the inventors"" experiments following the same procedures and conditions revealed that 2-cyclopentylidenecyclopentanone, i.e., a dimer of cyclopentanone, was preferentially produced and the yield of the target compound was below 1%. This literature is also silent on the use of the target compound as a perfume.
It is generally accepted that fragrances of compounds used as a perfume greatly vary even though there exists only a minor difference in chemical structure. Therefore, it is crucial for the development of novel perfumes to synthesize compounds having various substituents and closely examine fragrances of the compounds.
A primary object of the present invention is to provide a novel compound having a cyclopentanone structure or a cyclopentanol structure, which emits a floral or musk-tone fragrance.
Other objects of the present invention are to provide processes for producing the cyclopentanone or cyclopentanol compound, and a perfume composition comprising the same.
The present inventors have synthesized compounds with a cyclopentanone or cyclopentanol structure having introduced therein various cyclopentyl derivatives as substituent, and have closely examined fragrance of the cyclopentanone or cyclopentanol compounds. As the results of examination, it has been found that perfume compositions comprising a cyclopentanone or cyclopentanol compound having a specific cyclopentyl derivative substituent emit floral and powdery cosmetic-like fragrances and are useful for imparting the fragrances, and natural and fresh scent to variety of toiletries.
Thus, in a first aspect of the present invention, there is provided a composition comprising at least 60% by weight, based on the weight of the composition, of a cyclopentane compound having an oxygen-containing group and cyclopentylidene and/or cyclopentyl substituents, which is represented by the following general formula (1): 
wherein  independently represents a single bond or a double bond, R1 through R10 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, and xe2x80x94Y is xe2x80x94OH or xe2x95x90O.
In a second aspect of the invention, there is provided a perfume composition comprising as a fragrant odor-emitting ingredient a cyclopentane compound having an oxygen-containing group and cyclopentilidene and/or cyclopentyl substituents, which is represented by the above formula (1).
In a third aspect of the invention, there is provided a process for preparing a 2,5-dicyclopentylidenecyclopentanone compound represented by the following general formula (4): 
wherein R1 through R10 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, which comprises allowing a 2-cyclopentylidenecyclopentanone compound represented by the following general formula (2): 
wherein R1 through R4, R9 and R10 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, to react with a cyclopentanone compound represented by the following general formula (3): 
wherein R5 through R8 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, under alkaline conditions.
In a fourth aspect of the invention, there is provided a process for preparing a 2,5-dicyclopentylcyclopentanone compound represented by the following general formula (5): 
wherein R1 through R10 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, which comprises reducing with hydrogen a 2,5-dicyclopentylidenecyclopentanone compound represented by the above formula (4).
In a fifth aspect of the invention, there is provided a process for preparing a 2,5-dicyclopentylidenecyclopentanol compound represented by the following general formula (6): 
wherein R1 through R10 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, which comprises reducing a 2,5-dicyclopentylidenecyclopentanone compound represented by the above formula (4).
In a sixth aspect of the invention, there is provided a process for preparing a 2,5-dicyclopentylcyclopentanol compound represented by the following general formula (7): 
wherein R1 through R10 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, which comprises reducing with hydrogen a 2,5-dicyclopentylcyclopentanone compound represented by the above formula (5).
In a seventh aspect of the invention, there is provided a process for preparing a 2,5-dicyclopentylcyclopentanol compound represented by the above formula (7), which comprises reducing with hydrogen a 2,5-dicyclopentylidenecyclopentanol compound represented by the above formula (6).
Composition Comprising Cyclopentane Compound Having Oxygen-Containing Group and Cyclopentylidene and/or Cyclopentyl Substituents, of Formula (1)
The cyclopentane compounds having an oxygen-containing group and cyclopentylidene and/or cyclopentyl substituents, which are represented by the above formula (1), are classified into two types, i.e., those which have a cyclopentanonol structure (in formula (1), xe2x80x94Y is xe2x80x94OH), and those which have a cyclopentanone structure (in formula (1), xe2x80x94Y is xe2x95x90O). These compounds of formula (1) have 2,5-dicyclopentylidene substituents; 2,5-dicyclopentyl substituents; or 2-cyclopentilidene-5-cyclopentyl substituents.
Among the compounds of formula (1), those in which xe2x80x94Y is xe2x80x94OH include, for example, 2,5-dicyclopentylcyclopentan-1-ol, 2-cyclopentylidene-5-cyclopentylcyclopentan-1-ol and 2,5-dicyclopentylidene-cyclopentan-1-ol. Of these, 2,5-dicyclopentylcyclopentan-1-ol is preferable.
Among the compounds of formula (1), those in which xe2x80x94Y is xe2x95x90O include, for example, 2,5-dicyclopentylcyclopentanone, 2-cyclopentylidene-5-cyclopentylcyclopentanone and 2,5-dicyclopentylidenecyclopentanone. Of these, 2,5-dicyclopentylcyclopentanone is preferable.
The composition of the invention comprises at least 60% by weight, based on the weight of the composition, of a the compound of formula (1). The purity of the compound of formula (1), i.e., the content thereof in the composition, can be 99% or more.
Preparation of Cyclopentane Compound Having Oxygen-Containing Group and Cyclopentylidene and/or Cyclopentyl Substituents, of Formula (1)
(i) Preparation of 2,5-Dicyclopentylidenecyclopentanone Compound of Formula (4)
A 2-cyclopentylidenecyclopentanone compound of formula (2), which is one raw material for the preparation of a compound of formula (4), i.e., a compound of formula (1) wherein Y is xe2x95x90O, is prepared by an ordinary procedure, namely, by an homoaldol reaction of a cyclopentanone compound followed by dehydration reaction.
As a base used for providing alkaline conditions under which a compound of formula (2) reacts with a compound of formula (3) for the synthesis of a compound of formula (4), there can be mentioned, for example, sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, sodium hydroxide and potassium hydroxide. These bases may be used either alone or in combination. The amount of base is usually in the range of 0.1 to 2 moles, preferably 0.5 to 1.5 moles and more preferably 0.8 to 1.2 moles, per mole of a 2-cyclopentylidenecyclopentanone compound of formula (2).
A reaction medium used for the reaction of a compound of formula (2) with a compound of formula (3) for the synthesis of a compound of formula (4) is not particularly limited provided that the reaction medium is incapable of reacting with the base used. As examples of the reaction medium, there can be mentioned alcohols such as methanol and ethanol; aliphatic hydrocarbons such as hexane, heptane, octane, cyclopentane and cyclohexane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene; and ethers such as diethyl ether, dibutyl ether, tetrahydrofuran and dioxane. These mediums may be used either alone or in combination. For example, a mixed medium of an alcohol with one or more other mediums can be mentioned.
The amount of a cyclopentanone compound of formula (3) used for the synthesis of a 2,5-dicyclopentylidenecyclopentanone compound of formula (4) is usually in the range of 0.1 to 2 moles, preferably 0.5 to 1.5 moles and more preferably 0.8 to 1.2 moles, per mole of a 2-cyclopentylidenecyclopentanone compound of formula (2).
The reaction temperature for the synthesis of a 2,5-dicyclopentylidenecyclopentanone compound of formula (4) is usually in the range of 20 to 180xc2x0 C., preferably 40 to 140xc2x0 C. and more preferably 60 to 100xc2x0 C. The reaction pressure may be either reduced pressure or increased pressure. The reaction pressure is usually in the range of 0.5 to 2 atm, and preferably 0.8 to 1.2 atm.
After completion of the reaction for synthesis of a compound of formula (4), the reaction mixture is neutralized with an acid such as hydrochloric acid and is separated into an organic phase and an aqueous phase. The target compound is isolated and purified by a conventional procedure such as distillation and recrystallization.
(ii) Preparation of 2,5-Dicyclopentylcyclopentanone Compound of Formula (5), 2,5-Dicyclopentylidenecyclopentanol Compound of Formula (6), and 2,5-Dicyclopentylcyclopentanol Compound of Formula (7)
Hydrogen addition to the carbonxe2x80x94carbon double bonds of a 2,5-dicyclopentylidenecyclopentanone compound of formula (4) gives a 2,5-dicyclopentylcyclopentanone compound of formula (5), and reduction of the carbonyl group of the compound of formula (5) gives 2,5-dicyclopentylcyclopentanol compound of formula (7).
Reduction of the carbonyl group of a 2,5-dicyclopentylidenecyclopentanone compound of formula (4) gives 2,5-dicyclopentylidenecyclopentanol compound of formula (6), and hydrogen addition to the carbonxe2x80x94carbon double bonds of the compound of formula (6) gives 2,5-dicyclopentylcyclopentanol compound of formula (7).
The reduction reactions can be carried out by the conventional procedure. More specifically, reduction of a carbonyl group in the compound of formula (4) or the compound of formula (5) is preferably conducted by using, for example, sodium boron hydride (NaBH4), lithium aluminum hydride (LiAlH4) or di-isobutylaluminum hydride (iBu2AlH). Hydrogen addition to carbonxe2x80x94carbon double bonds in the compound of formula (4) or the compound of formula (6) is preferably conducted according to a catalytic hydrogenation reduction using a catalyst such as palladium, ruthenium, rhodium, platinum or Raney nickel.
After completion of the reactions for the synthesis of compounds of formulae (5) to (7), when a catalytic reduction using a catalyst is conducted, the catalyst used is separated by filtration; and when the reduction using NaBH4, LiAlH4 or iBu2AlH is conducted, the reaction mixture is neutralized with an acid, for example, hydrochloric acid, and then an organic phase is separated from an aqueous phase. The target compounds are isolated and purified by conventional means such as distillation and recrystallization.
Perfume Composition
The composition of the invention comprising at least 60% by weight, based on the weight of the composition, of the compound of (1) are used as a perfume composition. Among the compounds of formula (1); cyclopentanol compounds of formulae (6) and (7) and cyclopentanone compounds of formula (5) emit floral and powdery cosmetic-like fragrances and are preferable ingredients in perfume compositions. These compounds may be used either alone or in combination. 2,5-Dicyclopentylcyclopentanone of the formula shown in Example 2 below, and 2,5-dicyclopentylcyclopentanol of the formula shown in Example 5 below, emit a sweet floral or tropical fruity musk-tone fragrance, have a powerful and long-lasting musk effect, and are discoloring; and are especially preferable ingredients in perfume compositions.
A perfume composition comprising at least one compound selected from the compounds of formula (1) is useful for imparting fragrances to, for example, a perfume, a soap, a shampoo, a hair-treatment, a body shampoo, a detergent, a cosmetic, a hair-spray and an aromatic.
According to the need, conventional fragrance/flavor-imparting agents and fragrance/flavor-retaining agents can be incorporated in combination with the compound of formula (1) in the perfume composition of the invention. Auxiliaries, diluents and other additives such as enzymes, colorants, antioxidants, preservatives, germicides can also be incorporated. Further, nourishing and repairing agents such as crude drugs, vitamins, nutrients, and fats and fatty oils, and modifiers such as bleaching agents, deodorizers and softeners, can also be incorporated in combination with the compound of formula (1) in the perfume composition of the invention.
The invention will now be described specifically by the following examples that by no means limit the scope of the invention.